LONDON/SAN FRANCISCO (Reuters) - The owner of Avast Software has chosen Morgan Stanley and UBS to list the antivirus software business in a multi-million dollar initial public offering in London, sources familiar with the matter said.

The banks and CVC Capital Partners, which took control of the Prague-based company in 2014 in a deal which valued the company at $1 billion, declined to comment.

Avast’s IPO would be the largest ever British technology IPO if it goes ahead. However, it would have to contend with a tough market, which has seen several planned London listings pulled in late 2017.

CVC hired Rothschild after talking to a series of banks as part of a so-called beauty contest in October, sources said in November, to carry out preliminary work for the deal which included the selection of global coordinators and bookrunners. The sources said the company could be worth as much as $4 billion.

Avast previously filed to go public on Nasdaq in December 2011 but the listing was pulled in July 2012 due to tough market conditions.

Avast’s enterprise value has more than tripled in recent years following a series of bolt-on acquisitions including a $1.3 billion swoop on U.S. rival AVG Technologies in 2016 and the purchase of London-based optimisation software firm Piriform in July for an undisclosed amount.

Chief Executive Vincent Steckler told Reuters in 2015 that the company was then worth “upwards of $2 billion”.